Example: I am sure that your tax returns will not be audited, knock on wood.
Origin: One theory is that it originated in the middle ages when there were in circulation, pieces of the Holy Rood or Cross on which Jesus was crucified. To touch one of these was supposed to bring good luck hence touch wood for good luck. There were also several Holy Foreskins around at the time ..but that was a different story!
Alternatively, The Druids, who worshipped trees, especially Oaks, wore a piece of Oak around their neck to ward off evil spirits. Hence touch wood for good luck.
Alternatively, You knock on wood because of those wily Wood Sprites. In medieval times, people believed in mischievous creatures known as sprites. Sprites are actually spirits or ghosts who were reputed to enjoy causing trouble and wreaking havoc in the lives of the living. Among the most mischievous were wood sprites.
If you were to mention something good, the wood sprites would try to foul it up. The thought was that if you knocked on the wood when you said these things, the wood sprites would not be able to hear you because of the knocking sound. Hence they would leave you alone.
Originally, these irregular courts were resorted to in frontier communities, usually for the trial and condemnation of people who had committed offenses against the community. It's believed to have started out sometime around 1849 with the California gold rush. As for the name, historians have said that it may be an allusion to to the way these courts tried "jumpers" who seized the mining claims of others in the community.
Edwin Perkins, president of an early 1900's company called Onor-Maid, was marketing a product called called Fruit Smack, a fruit-flavored soft drink syrup. Fruit Smack was a popular alternative for those who couldn't afford a new drink called Coca Cola. But since the syrup was sold in bottles, the price was relatively expensive. Perkins noticed how successful the new gelatin product, Jell-O, was becoming, and decided to convert his syrup into a powdered form and sell it that way. He then renamed the product Kool-Aid, modeled loosely after the company's name.
